Radiator fan shroud



Patented Aug. 15, 1944 RADIATOR FAN SHROUD Otto A. Bossart, Racine, Wis., assignor to Perfex Corporation, Milwaukee, Wis., a corporation of Wisconsin Application March 17, 1943, Serial No. 479,479

2 Claims.

This invention relates in general to heat exchange and more particularly to cooling of internal combustion engines.

In liquid cooling of internal combustion engines, a fan driven by the internal combustion engine is usually used for forcing air through the radiator. In order to increase the efliciency of the fan it is common to place a fan shroud between the radiator and fan. This fan shroud serves to increase the fan efiiciency by preventing or reducing recirculation of air from the high pressure side of the fan to the low pressure side thereof. In certain types of internal com- ,bustion engines the fan is driven by a belt and adjustment of the belt tension is made by bodily shifting the fan. This arrangement in the past has necessitated the making of the fan opening in the fan shroud generally elliptical in shape so as to permit the necessary adjusting movement of the fan within the shroud. This making of the fan opening in the shroud larger than the fan, permits recirculation of air about the periphery of the fan and thus decreases its efficiency. The object of the present invention is to provide a fan shroud arrangement which provides for a close fit with the fan and which permits movement of the fan for adjusting the belt tension.

FOr a full disclosure of this invention, reference is made to the following detailed description, and to the accompanying drawing, in which Fig. 1 is a rear elevation of a radiator embodying the improved fan shroud arrangement; and

Fig. 2 is a side view of the radiator shown in Fig. 1.

Referring to the drawing, the radiator as shown is of conventional construction, consisting of side members I and 2 which are supported on angles 3 and 4 and which support a bottom tank 5 and a top tank 6, which in turn support the usual radiator core. A primary fan shroud member I is provided with flange portions 8 and is secured to the side members and tanks by means of screws 9. This primary fan shroud member extends rearwardly from the radiator and is formed with a rear wall H] which is provided with an elliptical opening H adjacent the fan blade I 2. The fan blade is carried by a shaft l3 which is journalled in an adjustable bearing M which is adjustably secured to a bracket IS. The bracket I5 is provided with an elongated slot l 6 through which the bearing extends. Adjustment of the tension of the fan belt I! is made by loosening a lock nut l8 and by turning a set screw 19. The elliptical opening in the primary fan shroud member insures that such adjusting movement of the fan will not result in the fan striking the fan shroud. This elliptical opening, however, has the disadvantage of permitting air to recirculate from the back of the fan to the front thereof, thereby reducing the amount of air drawn through the radiator.

In order to overcome this disadvantage, a secondary fan shroud member 20 is attached to the rear wall I0 of the primary shroud member 1. This secondary shroud member consists of a flat plate 2| which carries a circular ring 22 which surrounds the fan blade and which is approximately the same diameter as the fan blade. This ring 22 reduces recirculation of air about the edges of the fan blade to a minimum.

In order to permit adjustment of the fan for varying the belt tension, the secondary shroud member is secured to the primary shroud member by bolts 23 which fit through a circular opening in shroud member 1 and through elongated slots 24 in the other shroud member. The slots 24 extend in a direction parallel with the path of adjustment of the fan and thus permit movement of the secondary fan shroud member with the fan. When it is desired to adjust the position of the fan, the bolts 23 are loosened and then the fan is adjusted to obtain the desired belt tension. The secondary shroud member is then centered with respect to the fan and the bolts 23 are tightened for maintaining the shroud member in its new position.

From the foregoing description it will be apparent that this invention provides an extremely simple arrangement providing a snugly fitting fan shroud for a fan which must be adjusted in position for varying belt tension. Inasmuch as various changes may be made from the embodiment of the invention illustrated, without departing from the scope of the invention, it is desired to be limited only by the appended claims.

What is claimed is:

1. In a cooling system for an internal combustion engine, a radiator, a belt-driven fan for increasing the flow of air through the radiator, means for adjusting the position of the fan along a predetermined path of adjustment to vary the fan belt tension, a primary fan shroud secured to the radiator adjacent the fan, a secondary fan shroud cooperating with the primary fan shroud and having a circular opening of a diameter approximately the same as the fan, and means for adjusting said secondary fan shroud in a direction parallel with the path of adjustment of the fan for aligning the fan and secondary shroud regardless of the adjustment of the fan.

2. In a cooling system for an internal combustion engine, a radiator, a belt-driven fan for increasing the flow of air through the radiator, means for adjusting the position of the fan along a predetermined path of adjustment to vary the fan belt tension, aprimary tan shroud member secured to the radiator and having an elliptical opening with its major axis substantially parallel major axis being greater than the fan diameter by an amount approximately as large as the effective range of fan adjustment, a secondary fan shroud member arranged to surround the fan and having an opening approximately the same as the fan diameter, releasible means for securing said secondary shroud member to the primary shroud member, said lastmentioned means including slots .in one of the members extending in parallel with the path of adjustment of the fan. with said path of adjustment of the fan, said I OTTO A. BOSSART. 

